Serge Voronoff was one of the most respected surgeons of the early 20th century. His work received accolades around the globe, earning him ungodly amounts of money. He gave men back their youth.

Serge Voronoff grafted monkey testicles onto humans.

No, no, no, you read that right. We will repeat it: Serge Voronoff grafted monkey testicles onto humans... and he was lauded for it.

So how did this real-life Dr. Moreau come about? Voronoff's theory was that grafting testicles from younger animals would transpose their youth into older ones. He started with sheep and goats, and then moved onto humans. When demand for young testicles outgrew supply, Voronoff shifted to monkeys. (What a marvelous sentence that is, no?)

Voronoff didn't stop with testicles. He moved on to ovaries, first with monkey to human and then the reverse. He even tried to inseminate that monkey with human semen... it didn't work.

With time, it became obvious that those patients who claimed rejuvenation were victims of the placebo effect. Voronoff's work fell out of favor, and his reputation suffered as well.

SERGE VORONOFF GRAFTED MONKEY TESTICLES ONTO HUMANS!